If you assume the Wikipedia article , there are several problems.
Debugging running processes (e.g. ASP.NET)
The ability to connect the debugger to an already running process has also been removed ...
To debug SharePoint code, you need to attach the debugger to the "already running process" w3wp.exe (ASP.NET workflow). When uninstalling this function, you need to find a workaround, for example, trace calls or logging. This is much more inconvenient.
No integration with third-party tools
Microsoft "made a business decision not to allow extensibility of third-party sites in Express."
It also eliminates the integration of very useful and useful add-ons such as WSPBuilder in Visual Studio. These tools greatly simplify the development and deployment of SharePoint. (Note that you can run the real WSPBuilder tool at the command line, but you have not found useful debugging / deployment features and templates for new SharePoint items.)
To summarize : perhaps this is possible, but developing SharePoint can sometimes be quite complicated. Removing these features will be much more difficult.